The present invention relates generally to semiconductor sensor devices, and, more particularly, to a pressure sensor device having a side vent.
Semiconductor sensor devices, such as pressure sensors, are well known. Such devices use semiconductor pressure sensor dies to sense the ambient atmospheric pressure. These dies are susceptible to mechanical damage during packaging and environmental damage when in use, and thus they must be carefully packaged. Further, pressure sensor dies, such as piezo-resistive transducers (PRTs) and parameterized layout cells (P-cells), do not allow full encapsulation because that would impede their functionality.
FIG. 1(A) shows an cross-sectional side view of a conventional packaged semiconductor sensor device 100 having a metal lid 104. FIG. 1(B) shows a perspective top view of the sensor device 100 partially assembled, and FIG. 1(C) shows a perspective top view of the lid 104.
As shown in FIG. 1, a pressure sensor die (P-cell) 106, an acceleration-sensing die (G-cell) 108, and a micro-control unit die (MCU) 110 are mounted on a lead frame flag 112, electrically connected to lead frame leads 118 with bond wires (not shown), and covered with a pressure sensitive gel material 114, which enables the pressure of the ambient atmosphere to reach the pressure sensitive active region on the top side of the P-cell 106, while protecting all of the dies 106, 108, 110 and the bond wires from mechanical damage during packaging and environmental damage (e.g., contamination and/or corrosion) when in use. The entire die/substrate assembly is encased in a mold compound 102 and covered with the lid 104, which has a vent hole 116 that exposes the gel-covered P-cell 106 to ambient atmospheric pressure outside the sensor device 100.
One problem with the sensor device 100 is the high manufacturing cost due to the use of a pre-molded lead frame, the metal lid 104, and the large volume of the pressure sensitive gel material 114. Accordingly, it would be advantageous to have a more economical way to package dies in semiconductor sensor devices.